Prof. Rennan Barkana

Research

Prof. Rennan Barkana (Full Professor) focuses on the era of the formation of the first stars and resulting signatures in 21-cm radio waves. This includes such topics as cosmic dawn (early X-ray heating, Lyman-alpha coupling, Lyman-Werner feedback), cosmic reionization (stars and black holes as UV sources, photoheating feedback), dark matter (possible interactions that cool the cosmic gas, effects of the streaming velocity relative to normal matter), and the corresponding 21-cm signatures (in the sky-averaged global 21-cm signal, in the power spectrum of 21-cm fluctuations, and in 3-D intensity maps).

Research achievements include: showing that a surprising signal observed by the EDGES radio telescope could be the first proof of a non-gravitational interaction between dark matter and normal matter; pointing out that early X-ray sources likely had hard spectra, resulting in a delayed cosmic heating and a more complex 21-cm signal than previously expected; showing that early galaxies were affected by the streaming velocity of dark matter relative to normal matter in a way that predicts a clear observational signature.

Future directions include: comparing model predictions based on the above inputs with data from radio telescopes ranging from small global experiments to the Square Kilometre Array.